From 932ce5bb0058ad5e757bd83476e297404f1bcb8b Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@meshlink.io>
Date: Tue, 4 May 2021 21:53:27 +0200
Subject: [PATCH] Fix uninitialized data being passed to sendmsg().

Found by Valgrind.
---
 src/discovery.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/discovery.c b/src/discovery.c
index 948d786e..4d05f7bc 100644
--- a/src/discovery.c
+++ b/src/discovery.c
@@ -121,6 +121,8 @@ static void send_mdns_packet_ipv4(meshlink_handle_t *mesh, int fd, int index, co
 		struct cmsghdr align;
 	} u;
 
+	memset(&u, 0, sizeof(u));
+
 	struct msghdr msg = {
 		.msg_name = (struct sockaddr *) &dest->sa,
 		.msg_namelen = SALEN(dest->sa),
@@ -130,7 +132,6 @@ static void send_mdns_packet_ipv4(meshlink_handle_t *mesh, int fd, int index, co
 		.msg_controllen = sizeof(u.buf),
 	};
 
-
 	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
 	cmsg->cmsg_level = IPPROTO_IP;
 	cmsg->cmsg_type = IP_PKTINFO;
-- 
2.39.5